Naphtha splitter integration with hncc technology

ABSTRACT

Systems and methods for processing full range naphtha and producing light olefins and BTX are disclosed. Full range naphtha is separated in naphtha splitter to produce a light naphtha stream and a heavy naphtha stream. The heavy naphtha stream is then fed to a heavy naphtha catalytic cracker to produce a cracked stream. The effluent from the steam cracking unit and the effluent from the catalytic cracking unit may be flowed into an oil quench tower and are further separated in a separation unit to produce purified ethylene, propylene, butadiene, 1-butene, and BTX. The cracked stream maybe further processed. The light naphtha stream or both the lights stream combined with the light naphtha stream is fed to a steam cracker to produce an effluent stream comprising olefins. Effluent of the steam cracker is fed to the processing unit to separate light olefins. The C6+ hydrocarbons from the processes may be recycled.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/684,089, filed Jun. 12, 2018, which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention generally relates to methods of processing full range naphtha. More specifically, the present invention relates to methods of processing full range naphtha by splitting it in a naphtha splitter to produce light naphtha (that includes liquefied petroleum gas) and heavy naphtha, which are then steam cracked and catalytically cracked, respectively. The present invention also generally relates to a process for producing light olefins and BTX (benzene, toluene, and xylene), and more specifically, it relates to a process that integrates heavy naphtha catalytic cracking and steam cracking to produce light olefins and BTX.

BACKGROUND OF THE INVENTION

Light olefins (C₂ to C₄ olefins) are building blocks for many chemical processes. Light olefins are used to produce polyethylene, polypropylene, ethylene oxide, ethylene chloride, propylene oxide, and acrylic acid, which, in turn, are used in a wide variety of industries such as the plastic processing, construction, textile, and automotive industries. Generally, light olefins are produced by steam cracking naphtha. However, in this process, a large portion of effluent from steam cracking naphtha is hydrogenated and recycled back to the steam cracking unit, resulting in high energy consumption for producing light olefins. Single ring aromatics including benzene, toluene, and xylene (BTX) are chemicals commonly used for producing plastics and other polymers. For example light olefins are used to produce polyethylene, polypropylene, ethylene oxide, ethylene chloride, propylene oxide, and acrylic acid, which, in turn, are used in a wide variety of industries such as the plastic processing, construction, textile, and automotive industries. Benzene is a precursor for producing polystyrene, phenolic resins, polycarbonate, and nylon. Toluene is used for producing polyurethane and as a gasoline component. Xylene is feedstock for producing polyester fibers and phthalic anhydride. Conventionally, olefins are produced by steam cracking naphtha and/or paraffin dehydrogenation. BTX is typically produced by catalytic reforming of naphtha. As the demand for olefins and BTX has been consistently increasing for the last few decades, the current market supply for these chemicals may not be sufficient. Catalytic cracking of naphtha has become one of the commonly used methods for producing both light olefins and BTX. However, the overall efficiency for catalytic cracking of naphtha is relatively low because catalytic cracking of light portion of naphtha, which comprises primarily hydrocarbons having a boiling point of 30 to 90° C., generally requires severe reaction conditions (e.g., high temperatures) to achieve target yield of light olefins and BTX. Thus, the energy consumption for producing light olefins and BTX via catalytic cracking is relatively high, resulting in high production costs for light olefins and BTX via catalytic cracking naphtha. Thus, alternative processes for producing olefins and/or BTX are needed.

Heavy naphtha catalytic cracking (HNCC) is a process capable of producing both light olefins and BTX. It generally converts hydrocarbon mixture with final boiling point (FBP) less than 250° C. to light olefins and BTX. However, the lighter fraction of the hydrocarbon mixture fed to a heavy naphtha catalytic cracking unit consumes a large amount of energy due to higher reaction temperature, resulting in high production cost for light olefins and BTX.

Overall, while methods of producing light olefins and BTX exist, the need for improvements in this field persists in light of at least the aforementioned drawbacks.

BRIEF SUMMARY OF THE INVENTION

A solution to the above-mentioned problem associated with the production of light olefins and BTX using naphtha as a feedstock has been discovered. The solution resides in part is a method of producing light olefins and BTX that includes splitting the naphtha feed stream into light naphtha stream and heavy naphtha stream. The light naphtha is fed to a steam cracking unit and the heavy naphtha is fed to a heavy naphtha catalytic cracking unit. The effluent from both of the steam cracking unit and the heavy naphtha catalytic cracking unit are processed in the same separation unit. Separated C₆+ hydrocarbons are recycled to the heavy naphtha catalytic cracking unit and separated light paraffins (C₂-C₅ paraffins) are recycled to the steam cracking unit. This can be beneficial for at least reducing energy consumption in the production of light olefins and BTX by removing light naphtha from the feedstock of the catalytic cracking process and removing heavy naphtha fraction from the feedstock of steam cracking process. Notably, this method integrates the steam cracking unit and the catalytic cracking unit to optimize energy consumption and light olefins and BTX yield. More specifically, the steam cracking unit and the catalytic cracking unit use the same separation unit to separate and purify produced light olefins and BTX, further reducing the operating cost and capital expenditure such production.

The solution also resides in methods of processing full range naphtha that include splitting the full range naphtha to produce a heavy naphtha stream and light naphtha stream that includes liquefied petroleum gas (LPG). The heavy naphtha stream is subsequently catalytically cracked to produce a cracked stream that comprises light olefins and BTX. The light naphtha stream that includes LPG is steam cracked to produce additional light olefins. This can be beneficial for at least improving the energy efficiency of heavy naphtha catalytic cracking to produce light olefins and BTX, and increasing the productivity of olefins by producing additional light olefins by steam cracking the light naphtha fraction. Therefore, the methods of the present invention provide a technical solution to at least some of the problems associated with the currently available methods for producing light olefins and BTX mentioned above.

Embodiments of the invention include a method of producing olefins and/or BTX. The method comprises splitting a feed stream comprising naphtha that has an initial boiling point (IBP) in a range of 30 to 50° C. and a FBP in a range of 210 to 220° C. to form a first stream comprising heavy naphtha that has an IBP in a range of 60 to 65° C. and a FBP in a range of 210 to 220° C. and a second stream comprising light naphtha that has an IBP in a range of 30 to 35° C. and a FBP in a range of 40 to 60° C. The method further comprises contacting the first stream with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in the first stream to form a first intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene. The method further comprises subjecting the second stream to steam cracking conditions that comprises a temperature above 800° C. to convert hydrocarbons in the second stream and thereby form a second intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene. Embodiments of the invention include a method of producing olefins and/or BTX. The method comprises splitting a feed stream comprising naphtha that has an IBP in a range of 30 to 50° C. and a FBP in a range of 210 to 220° C. to form a first stream comprising heavy naphtha that has an IBP in a range of 60 to 65° C. and a FBP in a range of 210 to 220° C. and a second stream comprising light naphtha that has an initial boiling point in a range of 30 to 35° C. and a FBP in a range of 40 to 60° C. The method further comprises contacting the first stream with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in the first stream to form a first intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, xylene. The method further still comprises subjecting the second stream to steam cracking conditions that comprises a temperature above 800° C. to convert hydrocarbons in the second stream and thereby form a second intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene. The method further comprises flowing the first intermediate product stream and the second intermediate product stream to an oil quench tower. The method further comprises cooling the first intermediate product stream and the second intermediate product stream in the oil quench tower to produce an oil quench tower effluent stream. The method further still comprises separating the oil quench tower effluent stream into a product stream comprising primarily ethylene, a product stream comprising primarily propylene, and a product stream comprising primarily butadiene. Embodiments of the invention include a method of producing olefins and/or BTX. The method comprises splitting a feed stream comprising naphtha that has an IBP in a range of 30 to 50° C. and a FBP in a range of 210 to 220° C. to form a first stream comprising heavy naphtha that has an IBP in a range of 60 to 65° C. and a FBP in a range of 210 to 220° C. and a second stream comprising light naphtha that has an IBP in a range of 30 to 35° C. and a FBP in a range of 40 to 60° C. The method further comprises contacting the first stream with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in the first stream to form a first intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, xylene. The method further comprises subjecting, in a steam cracker, the second stream to steam cracking conditions that comprises a temperature above 800° C. to convert hydrocarbons in the second stream and thereby form a second intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene. The method further comprises flowing the first intermediate product stream and the second intermediate product stream to an oil quench tower. The method further still comprises cooling the first intermediate product stream and the second intermediate product stream in the oil quench tower to produce an oil quench tower effluent stream. The method further still comprises separating the oil quench tower effluent stream into a product stream comprising primarily ethylene, a product stream comprising primarily propylene, and a product stream comprising primarily butadiene. The method further comprises recovering a recycle stream resulting from the separating that comprises primarily recovering a recycle stream resulting from the separating step, wherein the recycle stream comprises primarily ethane, propane, n-butane, isobutane, 2-butene and recycling the recycle stream to the steam cracker.

Embodiments of the invention include a method of processing full range naphtha. The method comprises feeding the full range naphtha to a naphtha splitter. The full range naphtha has an IBP of 30° C. to 50° C. and a FBP of 210° C. to 220° C. The method further comprises separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60° C. to 65° C. and a FBP of 210° C. to 220° C. and a light naphtha stream having an IBP of 30° C. to 35° C. and a FBP of 40° C. to 60° C. The method further comprises catalytically cracking the heavy naphtha stream to produce a cracked stream. The method further still comprises processing the cracked stream to produce C₂ to C₄ olefins, benzene, toluene, and xylene. Embodiments of the invention include a method of processing full range naphtha. The method comprises feeding the full range naphtha to a naphtha splitter. The full range naphtha has an IBP of 30° C. to 50° C. and a FBP of 210° C. to 220° C. The method further comprises separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60° C. to 65° C. and a FBP of 210° C. to 220° C. and a light naphtha stream having an IBP of 30° C. to 35° C. and a FBP of 40° C. to 60° C. The method further comprises catalytically cracking the heavy naphtha stream to produce a cracked stream. The method further comprises processing the cracked stream to produce C₂ to C₄ olefins, benzene, toluene, and xylene. The method further still comprises steam cracking the light naphtha stream to produce olefins. Embodiments of the invention include a method of processing full range naphtha. The method comprises feeding the full range naphtha to a naphtha splitter. The full range naphtha has an IBP of 30° C. to 50° C. and a FBP of 210° C. to 220° C. The method further comprises separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60° C. to 65° C. and a FBP of 210° C. to 220° C. and a light naphtha stream having an IBP of 30° C. to 35° C. and a FBP of 40° C. to 60° C. The method further comprises catalytically cracking the heavy naphtha stream to produce a cracked stream. The method further comprises processing the cracked stream to produce a stream comprising primarily C₂ to C₄ olefins, benzene, toluene, xylene, collectively, a lights recycle stream comprising primarily C₂ to C₄ hydrocarbons, and a heavies recycle stream comprising primarily C₅ to C₁₂ hydrocarbons. The method further comprises combining the light naphtha stream with the lights stream to form a combined lights stream. The method further comprises steam cracking the combined lights stream to produce olefins.

Following includes definitions of terms and phrases used throughout this specification.

The terms “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%.

The terms “wt. %,” “vol. %” or “mol. %” refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol. % of component.

The term “substantially” and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

The terms “inhibiting” or “reducing” or “preventing” or “avoiding” or any variation of these terms, when used in the claims and/or the specification, include any measurable decrease or complete inhibition to achieve a desired result.

The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.

The term “raffinate,” as the term is used in the specification and/or claims, means the rest of a product stream, from which a target component or components have been removed.

The use of the words “a” or “an” when used in conjunction with the term “comprising,” “including,” “containing,” or “having” in the claims or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

The term “C_(n+) hydrocarbon” wherein n is a positive integer, e.g. 1, 2, 3, 4, or 5, as that term is used in the specification and/or claims, means any hydrocarbon having at least n number of carbon atom(s) per molecule.

The words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

The process of the present invention can “comprise,” “consist essentially of,” or “consist of” particular ingredients, components, compositions, etc., disclosed throughout the specification.

The term “primarily,” as that term is used in the specification and/or claims, means greater than any of 50 wt. %, 50 mol. %, and 50 vol. %. For example, “primarily” may include 50.1 wt. % to 100 wt. % and all values and ranges there between, 50.1 mol. % to 100 mol. % and all values and ranges there between, or 50.1 vol. % to 100 vol. % and all values and ranges there between.

Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a schematic diagram of a system for producing light olefins and BTX, according to embodiments of the invention; and

FIG. 2 shows a schematic flowchart of a method of producing light olefins and BTX, according to embodiments of the invention.

FIG. 3 shows a schematic diagram for a system of processing full range naphtha, according to embodiments of the invention; and

FIG. 4 shows a schematic flowchart for a method of processing full range naphtha, according to embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Currently, both light olefins and BTX can be produced by catalytic cracking of naphtha, e.g., heavy naphtha. Light olefins and BTX can also be produced by steam cracking naphtha. However, the overall conversion rate to light olefins and BTX for steam cracking naphtha is relatively low, resulting in large amounts of recycle stream back to the steam cracking unit and, consequently, high production cost. However, cracking the light fraction of full range naphtha increases the energy consumption of the process, e.g., the heavy naphtha catalytic cracking unit. The availability of heavy naphtha is generally limited. Therefore, the overall production efficiency for heavy naphtha catalytic cracking is low. The present invention provides a solution to at least one of the problems associated with olefins and BTX production. The solution is premised on a method that includes splitting a full range naphtha into a light naphtha stream and a heavy naphtha stream. The lights stream and/or the light naphtha stream are fed to a steam cracker to produce additional olefins, further improving production efficiency of light olefins. This method further includes catalytically cracking the heavy naphtha stream to produce olefins, BTX, and a lights stream, resulting in improved energy efficiency for heavy naphtha catalytic cracking. Therefore, the method is capable of reducing energy consumption for catalytic cracking by utilizing only heavy naphtha as the catalytic cracking feedstock and improving conversion rate and reducing energy consumption for steam cracking by utilizing only light naphtha as the steam cracking feedstock. Additionally, this method utilizes the same production separation system for the catalytic cracking unit and the steam cracking unit, resulting in reduced production cost and capital expenditure compared to conventional independent processes of steam cracking and catalytic cracking for light olefins and BTX production. These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.

A. System for Producing Olefins and BTX

In embodiments of the invention, the system for producing light olefins and BTX can include an integrated system comprising a naphtha splitting unit, a catalytic cracking unit, a steam cracking unit, and a product separation unit. With reference to FIG. 1, a schematic diagram is shown of system 100 that is capable of producing light olefins (e.g., C₂ and C₃ olefins) and BTX (benzene, toluene, xylene) with improved production efficiency and reduced production cost compared to conventional processes. According to embodiments of the invention, system 100 includes naphtha splitter 101 configured to receive and separate naphtha stream 11 into first stream 12 and second stream 13. In embodiments of the invention, first stream 12 comprises primarily heavy naphtha. Heavy naphtha may have an IBP of 60 to 65° C. and a FBP of 210 to 220° C. In embodiments of the invention, second stream 13 comprises primarily light naphtha. Light naphtha may have an IBP of 30 to 35° C. and a FBP of 40 to 60° C. In embodiments of the invention, naphtha splitter 101 may include one or more absorbers, one or more adsorbers, one or more distillation columns, or combinations thereof. In embodiments of the invention, naphtha splitter 101 may include a first outlet in fluid communication with steam cracker such that light naphtha stream flows from naphtha splitter 101 to the steam cracker. In embodiments of the invention, the steam cracker may be configured to crack light naphtha stream to form effluent stream comprising olefins. In embodiments of the invention, naphtha splitter may further include a second outlet in fluid communication with catalytic cracker. In embodiments of the invention, catalytic cracker is a heavy naphtha catalytic cracking unit adapted for heavy naphtha catalytic cracking. The naphtha splitter unit may comprise a series of distillation columns enabling the separation of light naphtha and heavy naphtha.

According to embodiments of the invention, a first outlet of feed splitting unit 101 is in fluid communication with an inlet of feed preheating and conditions unit 102 such that first stream 12 comprising primarily heavy naphtha flows from feed splitting unit 101 to feed preheating and conditioning unit 102. In embodiments of the invention, feed preheating and conditioning unit 102 is adapted to preheat first stream 12 to a temperature of 215 to 950° C. and all ranges and values there between. Feed preheating and conditioning unit 102 may be further adapted to separate (a) heavy stream 14 and (b) first BTX containing stream 16, from first stream 12. Feed preheating and conditioning unit 102 may be further adapted to mix steam with first stream 12 to produce catalytic cracking feed stream 15. In embodiments of the invention, catalytic cracking feed stream 15 has a volumetric ratio of steam to hydrocarbon weight ratio of 0.2 to 0.7, and all ranges and values there between including 0.3, 0.4, 0.5, and 0.6. In embodiments of the invention, catalytic cracking feed stream 15 has an IBP of 60 to 65° C. and a FBP of 210 to 220° C. According to embodiments of the invention, feed preheating and conditioning unit 102 comprises a heat exchanger configured to heat first stream 12. In embodiments, feed preheating and conditioning unit 102 may further comprise a preheated feed separator adapted to separate heavy stream 4 and first BTX containing stream 16 from first stream 12.

In embodiments of the invention, second stream 13 is mixed with steam to form steam cracking feed stream 17. Steam cracking feed stream 17 may have a steam to hydrocarbon volumetric ratio of 0.2 to 0.7 and all ranges and values there between including 0.3, 0.4, 0.5, and 0.6. According to embodiments of the invention, a second outlet of feed splitting unit 101 is in fluid communication with steam cracking unit 103 such that steam cracking feed stream 17 flows from feed splitting unit 101 to steam cracking unit 103. In embodiments of the invention, steam cracking unit 103 is configured to steam crack hydrocarbons of steam cracking feed stream 17 under reaction conditions sufficient to produce second intermediate product stream 18. Second intermediate product stream 18 may comprise ethylene, propylene, C₄ hydrocarbons, BTX, or combinations thereof.

According to embodiments of the invention, an outlet of feed preheating and conditioning unit 102 is in fluid communication with catalytic cracking unit 104 such that catalytic cracking feed stream 15 flows from feed preheating and conditioning unit 102 to catalytic cracking unit 104. In embodiments of the invention, catalytic cracking unit 104 is adapted to crack hydrocarbons of catalytic cracking feed stream 15 in presence of a catalyst under reaction conditions sufficient to produce first intermediate product stream 20. In embodiments of the invention, first intermediate product stream 20 comprises primarily ethylene, propylene, C₄ hydrocarbons, BTX, or combinations thereof. In embodiments of the invention, catalytic cracking unit 104 comprises one or more fluidized bed reactors, one or more fixed bed reactors, dense bed reactor, or combinations thereof. In embodiments of the invention, catalytic cracking unit 104 may contain a catalyst comprising one or more molecular sieve catalysts.

In embodiments of the invention, a first outlet of catalytic cracking unit 104 is in fluid communication with catalyst regeneration unit 106 such that spent catalyst of stream 19 from catalytic cracking unit 104 flows to catalyst regeneration unit 106. In embodiments of the invention, catalyst regenerating unit 106 is adapted to regenerate spent catalyst from catalytic cracking unit 104 to produce regenerated catalyst stream 22 and flue gas. According to embodiments of the invention, catalyst regenerating unit 106 is further adapted to heat boiler feed water stream 25 using flue gas heat to produce heated boiler feed water stream 26. In embodiments of the invention, catalyst regeneration unit 106 includes one or more furnaces.

An outlet of catalyst regeneration 106 may be in fluid communication with catalyst feeding unit 107 such that regenerated catalyst stream 22 flows from catalyst regeneration unit 106 to catalyst feeding unit 107. In embodiments of the invention, catalyst feeding unit 107 is configured to combine regenerated catalyst stream 22 with catalyst makeup stream 23 comprising fresh catalyst to form catalyst feed stream 24 and feed catalyst feed stream 24 to catalytic cracking unit 104.

In embodiments of the invention, a second outlet of catalytic cracking unit 104 is in fluid communication with process heat recovery unit 105 such that first intermediate product stream 20 flows from catalytic cracking unit 104 to process heat recovery unit 105. Process heat recovery unit 105 may be configured to cool first intermediate product stream 20 using heated boiler feed water stream 26 to produce steam stream 27 and cooled first intermediate product stream 21. In embodiments of the invention, an outlet of process heat recovery unit 105 is in fluid communication to catalyst regeneration unit 106 such that steam stream 27 flows to catalyst regeneration unit 106. In embodiments of the invention, steam stream 27 is heated to produce superheated steam stream 28. In embodiments of the invention, superheated steam stream 28 is at a temperature of 135 to 850° C. and all ranges and values there between. In embodiments of the invention, process heat recovery unit 105 includes one or more heat exchangers.

In embodiments of the invention, an outlet of process heat recovery unit 105 is in fluid communication with oil quench tower 108 such that cooled first intermediate product stream 21 flows from process heat recovery unit 105 to oil quench tower 108. According to embodiments of the invention, an outlet of steam cracking unit 103 is in fluid communication with oil quench tower 108 such that second intermediate product stream 18 flows from steam cracking unit 103 to oil quench tower 108. In embodiments of the invention, oil quench tower 108 is adapted to cool cooled first intermediate product stream 21 and second intermediate product stream 18 to a desired temperature.

According to embodiments of the invention, oil quench tower 108 is further adapted to separate a mixture of cooled first intermediate product stream 21 and second intermediate product stream 18 into fuel oil stream 30 comprising primarily fuel oil and oil quench tower effluent stream 29. In embodiments of the invention, an outlet of oil quench tower 108 may be in fluid communication with catalytic cracking unit 104 such that fuel oil stream 18 flows to catalytic cracking unit 104 as fuel for providing heat for catalytic cracking unit 104.

In embodiments of the invention, a second outlet of oil quench tower 108 is in fluid communication with an inlet of water quench tower 109 such that oil quench tower effluent stream 29 flows from oil quench tower 108 to water quench tower 109. According to embodiments of the invention, water quench tower 109 is adapted to cool oil quench tower effluent stream 29 to form water quenched stream 31.

According to embodiments of the invention, an outlet of water quench tower 109 is in fluid communication with first compressor 110 such that water quenched stream 31 flows from water quench tower to first compressor 110. In embodiments of the invention, first compressor 110 is adapted to compress water quenched stream 31. In embodiments of the invention, first compressor 110 is a two-stage compressor. First compressor 110 may be further adapted to separate water quenched stream 31 to C₆+ containing stream 32 and first compressed product stream 33. In embodiments of the invention, C₆+ containing stream 32 comprises BTX, C₁-C₅ hydrocarbons, or combinations thereof. First compressed product stream 33 may comprise primarily C₁-C₄ hydrocarbons, or combinations thereof.

In embodiments of the invention, an outlet of C₆+ containing stream 32 is in fluid communication with de-hexanizer 111 such that C₆+ containing stream 32 flows from first compressor 110 to de-hexanizer 111. In embodiments of the invention, de-hexanizer 111 is adapted to separate C₆+ containing stream 32 into a plurality of streams including one or more of C₆+ stream 35 comprising C₆+ hydrocarbons recycled to feed preheating and conditioning unit 102, BTX stream 34 comprising primarily BTX, and returning stream 36 flowing back to first compressor 110.

In embodiments of the invention, an outlet of de-hexanizer 111 is in fluid communication with aromatics extraction unit 112 such that BTX stream 34 flows from de-hexaner 111 to aromatics extraction unit 112. In embodiments of the invention, aromatics extraction unit 112 is adapted to extract benzene, toluene, xylene from BTX stream 34 to produce BTX product stream 37. In embodiments of the invention, aromatics extraction unit 112 comprises one or more extraction columns. In embodiments of the invention, an outlet of feed-preheating and conditioning unit 102 is in fluid communication with aromatics extraction unit 112 such that first BTX containing stream 16 flows from feed preheating and conditioning unit to aromatics extraction unit 112.

In embodiments of the invention, first compressed product stream 33 is subsequently flowed through water wash unit 113, first caustic tower 114, acid and oxygen removal unit 115, second caustic tower 116, second compressor 117 to form second compressed product stream 38. In embodiments of the invention, water wash unit 113 is adapted to remove impurities from first compressed product stream 33. First caustic tower 114 may be adapted to remove impurities from first compressed product stream 33. Acid and oxygen removal unit 115 may be adapted to remove acidic compounds and oxygen from first compressed product stream 33. Second caustic tower 116 may be adapted to further remove additional impurities from first compressed product stream 33. Second compressor 117 may be adapted to further compress first compressed product stream 33. Second compressor 117 may further compress first compressed product stream 33.

According to embodiments of the invention, second compressor 117 is in fluid communication with de-methanizer 118 such that second compressed stream 38 flows from second compressor 117 to de-methanizer 118. De-methanizer 118 may be adapted to remove methane and hydrogen from second compressed stream 38 to form de-methanized stream 39, which flows from de-methanizer 118 to de-ethanizer 119. In embodiments of the invention, de-ethanizer 119 is adapted to separate de-methanized stream 39 to C₂ stream 40 and de-ethanized stream 41. In embodiments of the invention, C₂ stream 40 is split in C₂ splitter 121 into ethylene stream 42 and ethane stream 43. In embodiments of the invention, ethylene stream comprises 20 to 99% by weight ethylene and all ranges there between.

In embodiments of the invention, de-ethanized stream 41 is flowed to de-propanizer 120 adapted to separate de-ethanized stream 41 into C₃ stream 44 comprising propane and propylene, and de-propanized stream 45. According to embodiments of the invention, C₃ stream 44 is flowed through MAPD hydrogenation unit 122 to remove methyl acetylene and propadiene from C₃ stream 44 to form hydrogenated C₃ stream 46 comprising primarily propane and propylene. Hydrogenated C₃ stream 46 may be further split in C₃ splitter 123 into propylene stream 47 comprising 20 to 99% by weight propylene and propane stream 48 comprising primarily propane.

According to embodiments of the invention, de-propanized stream 45 is flowed to de-butanizer 124 adapted to separate de-propanized stream 45 into (1) de-butanized stream 50 and (2) C₄ stream 49 comprising n-butane, 1-butene, 2-butene, butadiene, isobutylene, isobutane, or combinations thereof.

In embodiments of the invention, C₄ stream 49 is flowed to butadiene and 1-butene extraction unit 125 adapted to separate C₄ stream 49 into butadiene and 1-butene stream 51 comprising primarily butadiene and 1-butene collectively, and raffinate stream 52 comprising n-butane, isobutane, 2-butene, isobutylene, or combinations thereof. In embodiments of the invention, an outlet of de-butanizer 124 is in fluid communication with an inlet of de-hexanizer 111 such that de-butanized stream 50 flows from de-butanizer 124 to de-hexanizer 111. According to embodiments of the invention, ethane stream 43, propane stream 48, raffinate stream 52, or combinations thereof are recycled steam cracking unit 103.

In embodiments, each of de-methanizer 118, de-ethanizer 119, de-propanizer 120, de-butanizer 124, and de-hexanizer 111 may comprise one or more distillation columns. In embodiments of the invention, each of C₂ splitter 121, and C₃ splitter 123 includes one or more distillation columns.

B. Method of Producing Light Olefins and BTX

As shown in FIG. 2, embodiments of the invention include method 200 for producing light olefins and BTX. Method 200 may be implemented by system 100, as shown in FIG. 1. According to embodiments of the invention, method 200 comprises splitting a feed stream comprising naphtha (naphtha stream 11) in naphtha splitter 101 to form first stream 12 and second stream 13, as shown in block 201. In embodiments of the invention, naphtha stream 11 comprises hydrocarbons that have an IBP in a range of 30 to 35° C. and a FBP in a range of 210 to 220° C. First stream 12 may comprise heavy naphtha that has an IBP in a range of 60 to 65° C. and all ranges and values there between including 61° C., 62° C., 63° C., and 64° C., and a FBP in a range of 210 to 220° C. and all ranges and values there between including ranges of 210 to 211° C., 211 to 212° C., 212 to 213° C., 213 to 214° C., 214 to 215° C., 215 to 216° C., 216 to 217° C., 217 to 218° C., 218 to 219° C., and 219 to 220° C. Second stream 13 may comprise light naphtha that has an IBP in a range of 30 to 35° C. and all ranges and values there between including 31° C., 32° C., 33° C., and 34° C. and a FBP in a range of 40 to 60° C. and all ranges and values there between including 40 to 41° C., 41 to 42° C., 42 to 43° C., 43 to 44° C., 44 to 45° C., 45 to 46° C., 46 to 47° C., 47 to 48° C., 48 to 49° C., 49 to 50° C., 50 to 51° C., 51 to 52° C., 52 to 53° C., 53 to 54° C., 54 to 55° C., 55 to 56° C., 56 to 57° C., 57 to 58° C., 58 to 59° C., and 59 to 60° C. In embodiments of the invention, naphtha splitter 101 comprises a distillation unit. Naphtha splitter 101 may be operated at an operating temperature of 35 to 50° C. and all ranges and values there between including ranges of 35 to 36° C., 36 to 37° C., 37 to 38° C., 38 to 39° C., 39 to 40° C., 40 to 41° C., 41 to 42° C., 42 to 43° C., 43 to 44° C., 44 to 45° C., 45 to 46° C., 46 to 47° C., 47 to 48° C., 48 to 49° C., and 49 to 50° C. The process conditions for naphtha splitter 101 may further include an operating pressure of 1 to 3 bar and all ranges and values there between including 1 to 1.2 bar, 1.2 to 1.4 bar, 1.4 to 1.6 bar, 1.6 to 1.8 bar, 1.8 to 2.0 bar, 2.0 to 2.2 bar, 2.2 to 2.4 bar, 2.4 to 2.6 bar, 2.6 to 2.8 bar, and 2.8 to 3.0 bar.

In embodiments of the invention, first stream 12 is preheated and mixed with steam in feed preheating and conditioning unit 102. In embodiments of the invention, first stream 12 is further separated in preheating and conditioning unit 102 into preheated and conditioned first stream 15, first BTX containing stream 16, and heavy stream 14. In embodiments of the invention, first BTX containing stream 16 may include 10 to 40 wt. % BTX and 20 to 70 wt. % C₂ to C₄ olefins BTX and all ranges and values there between. Heavy stream 14 may include primarily 10 to 40 wt. % C₅ and 20 to 80 wt. % C₆ to C₁₂ hydrocarbons.

According to embodiments of the invention, as shown in block 202, method 200 includes, in catalytic cracking unit 104, contacting preheated and conditioned first stream 15 with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in preheated and conditioned stream 15 to form first intermediate product stream 20. In embodiments of the invention, preheated and conditioned first stream 15 has a volumetric ratio of steam to the combined lights stream in a range of 0.2 to 0.7, and all ranges and values there between including 0.3, 0.4, 0.5, and 0.6. In embodiments of the invention, the catalyst comprises a molecular sieve based catalyst. The catalytic cracking conditions may include a reaction temperature of 800 to 950° C. and all ranges and values there between. The catalytic cracking conditions may include a reaction pressure of 1 to 4 bar and all ranges and values there between. In embodiments of the invention, first intermediate product stream 20 comprises ethylene, ethane, propylene, propane, C₄ hydrocarbons, methane, hydrogen, C₅+ hydrocarbons, or combinations thereof. In embodiments of the invention, the C₅+ hydrocarbons include benzene, toluene, and xylene. According to embodiments of the invention, first intermediate product stream 20 comprises 1 to 90 wt. % ethylene, 1 to 90 wt. % propylene, 1 to 90 wt. % C₄ hydrocarbons, 1 to 90 wt. % BTX, and 1 to 90 wt. % C₅+ hydrocarbons.

According to embodiments of the invention, as shown in block 203, method 200 includes subjecting, in a steam cracker, second stream 13 to steam cracking conditions sufficient to convert hydrocarbons in second stream thereby forming second intermediate product stream 18. In embodiments of the invention, steam cracking conditions include a volumetric ratio of steam to the combined lights stream in a range of 0.2 to 0.7, and all ranges and values there between including 0.3, 0.4, 0.5, and 0.6. In embodiments of the invention, steam cracking conditions include a reaction temperature of 800 to 950° C. and all ranges and values there between. Steam cracking conditions may include a residence time of 5 to 10000 ms and all ranges and values there between there between including ranges of 5 to 10 ms, 10 to 30 ms, 30 to 50 ms, 50 to 80 ms, 80 to 100 ms, 100 to 500 ms, 500 to 1000 ms, 1000 to 2000 ms, 2000 to 3000 ms, 3000 to 4000 ms, 4000 to 5000 ms, 5000 to 6000 ms, 6000 to 7000 ms, 7000 to 8000 ms, 8000 to 9000 ms, and 9000 to 10000 ms. According to embodiments of the invention, second intermediate product stream 18 comprises ethylene, ethane, propylene, propane, C₄ hydrocarbons, methane, hydrogen, C₅+ hydrocarbons, or combinations thereof. In embodiments of the invention, the C₅+ hydrocarbons include benzene, toluene, and xylene. In embodiments of the invention, second intermediate product stream 18 comprises 1 to 90 wt. % ethylene, 1 to 90 wt. % propylene, 1 to 90 wt. % C₄ hydrocarbons, 1 to 90 wt. % BTX, and 1 to 90 wt. % C₅+ hydrocarbons.

In embodiments of the invention, process heat of first intermediate product stream 20 is recovered in process heat recovery unit 105 to produce steam stream 27 and cooled first intermediate product stream 21. According to embodiments of the invention, as shown in block 204, method 200 further includes flowing cooled first intermediate product stream 21 and second intermediate product stream 18 to oil quench tower 108. In embodiments of the invention, method 200 further includes cooling cooled first intermediate product stream 21 and second intermediate product stream 18 in oil quench tower 108 to produce oil quench tower effluent stream 29, as shown in block 205. Oil quench tower 108 may be operated at a suitable residence time. In embodiments of the invention, fuel oil in cooled first intermediate product stream 21 and second intermediate product stream 18 is separated in oil quench tower 108 and recycled to catalytic cracking unit 104.

In embodiments of the invention, oil quench tower effluent stream 29 is further quenched in water quench tower 109. According to embodiments of the invention, as shown in block 206, method 200 further includes separating oil quench tower effluent stream 29 into a plurality of product streams including a product stream comprising primarily ethylene (ethylene stream 42), a product stream comprising primarily propylene (propylene stream 47), a product stream comprising primarily butadiene, and a product stream comprising primarily 1-butene. In embodiments of the invention, the plurality of product streams further include BTX product stream 37 comprising primarily benzene, toluene, and xylene, collectively. In embodiments of the invention, the separating at block 206 is carried out in a separation unit comprising one or more compressing units, one or more water quench towers, one or more distillation columns, one or more extraction units, one or more caustic towers, one or more washing units, or combinations thereof. In embodiments of the invention, the separation unit used for separating at block 206 includes water quench tower 109, first compressor 110, water wash unit 113, first caustic tower 114, acid and oxygen removal unit 115, second caustic tower 116, second compressor 117, de-methanizer 118, de-ethanizer 119, C₂ splitter 121, de-propanizer 120, MAPD hydrogenation unit 122, C₃ splitter 123, de-butanizer 124, butadiene and 1-butene extraction unit 125, dehexanizer 111, aromatics extraction unit 112, as shown in FIG. 1.

According to embodiments of the invention, as shown in block 207, method 200 further includes recovering a recycle stream resulting from the separating at block 206 that comprises primarily ethane, propane, n-butane, isobutane, 2-butene, isobutylene and recycling the recycle stream to steam cracking unit 103. In embodiments of the invention, the ethane in the recycle stream is recovered from ethane stream 43. The propane in the recycle stream may be recovered from propane stream 48. The n-butane, isobutane, 2-butene, and isobutylene in the recycle stream may be recovered from raffinate stream 52. According to embodiments of the invention, as shown in block 208, method 200 further includes recovering a second recycle stream (C₆+ stream 35) comprising primarily C₆+ hydrocarbons and recycling the second recycle stream to feed preheating and conditioning unit 102 for further catalytic cracking. Although embodiments of the present invention have been described with reference to blocks of FIG. 2, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 2. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 2.

C. Systems for Processing Full Range Naphtha and Producing Olefins and BTX

In embodiments of the invention, the system for processing full range naphtha and producing olefins and BTX may include a heavy naphtha catalytic cracking unit integrated with a naphtha splitter and a steam cracker. With reference to FIG. 3, a schematic diagram is shown of system 100 that is adapted to process full range naphtha to produce light olefins (C₂ to C₄ olefins) and BTX (benzene, toluene, xylene) with improved production efficiency compared to a conventional heavy naphtha catalytic cracking process. According to embodiments of the invention, system 300 includes naphtha splitter 301 configured to separate full range naphtha stream 311 into light naphtha stream 312 and heavy naphtha stream 313.

According to embodiments of the invention, full range naphtha includes a crude oil fraction that has an IBP of 30 to 50° C. and a FBP of 210 to 220° C. The full range naphtha may be obtained from atmospheric and vacuum crude oil distillation. In embodiments of the invention, naphtha splitter 301 may include one or more absorbers, one or more adsorbers, one or more distillation columns, or combinations thereof. In embodiments of the invention, naphtha splitter 301 may include a first outlet in fluid communication with steam cracker 302 such that light naphtha stream 312 flows from naphtha splitter 301 to steam cracker 302. In embodiments of the invention, steam cracker 302 may be configured to crack light naphtha stream 312 to form effluent stream 315 comprising olefins. In embodiments of the invention, naphtha splitter 301 may further include a second outlet in fluid communication with catalytic cracker 303. In embodiments of the invention, catalytic cracker 303 is a heavy naphtha catalytic cracking unit adapted for heavy naphtha catalytic cracking. The naphtha splitter unit may comprise a series of distillation columns enabling the separation of light naphtha and heavy naphtha. According to embodiments of the invention, catalytic cracker 303 may comprise a fixed bed reactor, a fluidized bed reactor, dense bed reactor, or combinations thereof. In embodiments of the invention, catalytic cracker 303 may include a catalyst comprising one or more molecular sieve catalysts. In embodiments of the invention, catalytic cracker 303 is configured to crack heavy naphtha stream 313 to form cracked stream 314 comprising olefins and BTX. In embodiments of the invention, catalytic cracker 303 may include an outlet in fluid communication with a first inlet of processing unit 304 such that cracked stream 314 flows from catalytic cracker 303 to processing unit 304. According to embodiments of the invention, processing unit may comprise a second inlet in fluid communication with an outlet of steam cracker 302 such that effluent stream 315 flows from steam cracker to processing unit 304. Alternatively or additionally, cracked stream 314 and effluent stream 315 may be combined before flowing to processing unit 304. In embodiments of the invention, processing unit 304 may be adapted to separate cracked stream 314 from catalytic cracker and/or effluent stream 315 from steam cracker 302 to form (a) olefins and BTX stream 316 comprising primarily olefins and BTX, collectively, (b) lights recycle stream 317, and (c) heavies recycle stream 318. According to embodiments of the invention, non-limiting examples of processing unit 304 may include compressor, heat exchangers, separation columns, reactors, absorbers, adsorbers, distillation column, pumps and dryers, or combinations thereof. In embodiments of the invention, processing unit 304 may include a first outlet in fluid communication with the inlet of steam cracker 302 such that lights recycle stream 317 flows from processing unit 304 to steam cracker 302. In embodiments of the invention, processing unit 304 may include a second outlet in fluid communication with the inlet of catalytic cracker 303 such that heavies recycle stream 318 flows from processing unit 304 to catalytic cracker 303. In embodiments of the invention, processing unit 304 may further include a third outlet configured to release olefins and BTX stream 316 there from. In embodiments of the invention, the third outlet of processing unit 304 may be in fluid communication with a purification unit, which is configured to further separate and/or purify olefins and/or BTX. In embodiments of the invention, the purification unit may include distillation columns, extractive columns, extractive distillation columns, reactors, membrane separators and dryers, or combinations thereof.

D. Methods for Processing Full Range Naphtha and Producing Olefins and BTX

Methods of processing full range naphtha and producing olefins and BTX have been discovered to expand the feedstock availability for catalytic cracker 303 (heavy naphtha catalytic cracker) and improve the production efficiency of the heavy naphtha catalytic cracker. As shown in FIG. 4, embodiments of the invention include method 400 for processing full range naphtha. Method 400 may be implemented by system 300, as shown in FIG. 3. According to embodiments of the invention, as shown in block 401, method 400 may include feeding full range naphtha stream 311 to naphtha splitter 301. In embodiments of the invention, the full range naphtha has an IBP of 30 to 50° C. and all ranges and values there between including 30 to 31° C., 31 to 32° C., 32 to 33° C., 33 to 34° C., 34 to 35° C., 35 to 36° C., 36 to 37° C., 37 to 38° C., 38 to 39° C., 39 to 40° C., 40 to 41° C., 41 to 42° C., 42 to 43° C., 43 to 44° C., 44 to 45° C., 45 to 46° C., 46 to 47° C., 47 to 48° C., 48 to 49° C., and 49 to 50° C. The full range naphtha may have a FBP of 210 to 220° C. and all ranges and values there between including ranges of 210 to 211° C., 211 to 212° C., 212 to 213° C., 213 to 214° C., 214 to 215° C., 215 to 216° C., 216 to 217° C., 217 to 218° C., 218 to 219° C., and 219 to 220° C.

According to embodiments of the invention, method 400 may further include separating the full range naphtha by naphtha splitter 301 to produce heavy naphtha stream 313 and light naphtha stream 312, as shown in block 402. In embodiments of the invention, the heavy naphtha (of heavy naphtha stream 313) may have an IBP of 60 to 65° C. and all ranges and values there between including 61° C., 62° C., 63° C., and 64° C. The heavy naphtha (of heavy naphtha stream 313) may have a FBP in a range of 210 to 220° C. and all ranges and values there between including ranges of 210 to 211° C., 211 to 212° C., 212 to 213° C., 213 to 214° C., 214 to 215° C., 215 to 216° C., 216 to 217° C., 217 to 218° C., 218 to 219° C., and 219 to 220° C. In embodiments of the invention, the light naphtha (of light naphtha stream 312) may have an IBP in a range of 30 to 35° C. and all ranges and values there between including 31° C., 32° C., 33° C., and 34° C. The light naphtha (of light naphtha stream 312) may have a FBP in a range of 40 to 60° C. and all ranges and values there between including 40 to 41° C., 41 to 42° C., 42 to 43° C., 43 to 44° C., 44 to 45° C., 45 to 46° C., 46 to 47° C., 47 to 48° C., 48 to 49° C., 49 to 50° C., 50 to 51° C., 51 to 52° C., 52 to 53° C., 53 to 54° C., 54 to 55° C., 55 to 56° C., 56 to 57° C., 57 to 58° C., 58 to 59° C., and 59 to 60° C.

In embodiments of the invention, the process conditions for naphtha splitter 301 include an operating temperature of 35 to 50° C. and all ranges and values there between including ranges of 35 to 36° C., 36 to 37° C., 37 to 38° C., 38 to 39° C., 39 to 40° C., 40 to 41° C., 41 to 42° C., 42 to 43° C., 43 to 44° C., 44 to 45° C., 45 to 46° C., 46 to 47° C., 47 to 48° C., 48 to 49° C., and 49 to 50° C. The process conditions for naphtha splitter 101 may further include an operating pressure of 1 to 3 bar and all ranges and values there between including 1 to 1.2 bar, 1.2 to 1.4 bar, 1.4 to 1.6 bar, 1.6 to 1.8 bar, 1.8 to 2.0 bar, 2.0 to 2.2 bar, 2.2 to 2.4 bar, 2.4 to 2.6 bar, 2.6 to 2.8 bar, and 2.8 to 3.0 bar.

According to embodiments of the invention, method 400 may further include catalytically cracking heavy naphtha stream 313 to produce cracked stream 314, as shown in block 403. In embodiments of the invention, cracked stream 314 may include 10 to 40 wt. % BTX, 20 to 70 wt. % C₂ to C₄ olefins, and 5 to 15 wt. % H2 to CH₄. In embodiments of the invention, the process conditions for catalytic cracker 303 include an operating temperature in a range of 600 to 750° C. and all ranges and values there between including 600 to 610° C., 610 to 620° C., 620 to 630° C., 630 to 640° C., 640 to 650° C., 650 to 660° C., 660 to 670° C., 670 to 680° C., 680 to 690° C., 690 to 700° C., 700 to 710° C., 710 to 720° C., 720 to 730° C., 730 to 740° C., and 740 to 750° C. The process conditions for catalytic cracker 303 may further include an operating pressure of 1 to 4 bar and all ranges and values there between including ranges of 1 to 1.2 bar, 1.2 to 1.4 bar, 1.4 to 1.6 bar, 1.6 to 1.8 bar, 1.8 to 2.0 bar, 2.0 to 2.2 bar, 2.2 to 2.4 bar, 2.4 to 2.6 bar, 2.6 to 2.8 bar, 2.8 to 3.0 bar, 3.0 to 3.2 bar, 3.2 to 3.4 bar, 3.4 to 3.6 bar, 3.6 to 3.8 bar, and 3.8 to 4.0 bar.

According to embodiments of the invention, as shown in block 404, method 400 may further include processing cracked stream 314 in processing unit 304 to produce olefins and BTX stream 316, lights stream 317 and heavies stream 318. In embodiments of the invention, olefins and BTX stream 316 may include 10 to 40 wt. % BTX and 20 to 70 wt. % C₂ to C₄ olefins. Lights stream 317 may include primarily 20 to 50 wt. % ethane, 10 to 30 wt. % propane, and 20 to 60 wt. % butane. Heavies stream 318 may include primarily 10 to 40 wt. % C₅ and 20 to 80 wt. % C₆ to C₁₂ hydrocarbons.

In embodiments of the invention, as shown in block 405, method 400 may further include combining light naphtha stream 312 with lights stream 317 to form a combined lights stream. Method 400 may further include steam cracking the combined lights stream in steam cracker 302 to produce effluent stream 315 comprising olefins, as shown in block 406. In embodiments of the invention, process conditions of steam cracker 302 may include an operating temperature in a range of 800 to 950° C. and all ranges and values there between including ranges of 800 to 810° C., 810 to 820° C., 820 to 830° C., 830 to 840° C., 840 to 850° C., 850 to 860° C., 860 to 870° C., 870 to 880° C., 880 to 890° C., 890 to 900° C., 900 to 910° C., 910 to 920° C., 920 to 930° C., 930 to 940° C., and 940 to 950° C. The process conditions of steam cracker 302 may include a residence time in a range of 5 to 10000 ms and all ranges and values there between including ranges of 5 to 10 ms, 10 to 30 ms, 30 to 50 ms, 50 to 80 ms, 80 to 100 ms, 100 to 500 ms, 500 to 1000 ms, 1000 to 2000 ms, 2000 to 3000 ms, 3000 to 4000 ms, 4000 to 5000 ms, 5000 to 6000 ms, 6000 to 7000 ms, 7000 to 8000 ms, 8000 to 9000 ms, and 9000 to 10000 ms. In embodiments of the invention, the process conditions of steam cracker 302 may include a volumetric ratio of steam to the combined lights stream in a range of 0.2 to 0.7, and all ranges and values there between including 0.3, 0.4, 0.5, and 0.6.

In embodiments of the invention, as shown in block 407, method 400 may further include flowing effluent stream 315 from steam cracker 302 to processing unit 304 to separate olefins from effluent stream 315. In embodiments of the invention, olefins separated from effluent stream 315 may be included in olefins and BTX stream 316. According to embodiments of the invention, method 400 may further include recycling heavies stream 318 to catalytic cracker 303, as shown in block 408. In embodiments of the invention, recycling at block 408 may include combining heavy naphtha stream 313 with heavies stream 318 to form a combined heavies stream and feeding the combined heavies stream to catalytic cracker 303. According to embodiments of the invention, method 400 may further include purifying olefins and BTX stream 316 to produce purified C₂ to C₄ olefins, benzene, toluene, and xylene.

Although embodiments of the present invention have been described with reference to blocks of FIG. 4, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 4. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 4.

In the context of the present invention, embodiments 1-33 are described. Embodiment 1 is a method of processing full range naphtha. The method includes feeding the full range naphtha to a naphtha splitter, the full range naphtha having an IBP of 30 to 50° C. and a FBP of 210 to 220° C. The method further includes separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60 to 65° C. and a FBP of 210 to 220° C. and a light naphtha stream having an IBP of 30 to 35° C. and a FBP of 40 to 60° C. The method also includes catalytically cracking the heavy naphtha stream to produce a cracked stream, and processing the cracked stream in a processing unit to produce C₂ to C₄ olefins, benzene, toluene, and xylene. Embodiment 2 is the method of embodiment 1, further including steam cracking the light naphtha stream to produce olefins. Embodiment 3 is the method of either of embodiments 1 or 2, wherein the processing further produces a lights stream containing primarily C₂ to C₄ hydrocarbons, and a heavies stream containing primarily C₅ to C₁₂ hydrocarbons. Embodiment 4 is the method of embodiment 3, further including combining the light naphtha stream with the lights stream to form a combined lights stream, and steam cracking the combined lights stream to produce a cracked lights stream containing olefins. Embodiment 5 is the method of embodiment 4, further including processing the cracked lights stream in the processing unit to produce additional C₂ to C₄ olefins. Embodiment 6 is the method of either of embodiments 4 or 5, wherein the steam cracking is performed under process conditions including a cracking temperature of 800 to 950° C. and a residence time of 5 to 10000 ms. Embodiment 7 is the method of any of embodiments 3 to 6, further including combining the heavies stream and the heavy naphtha stream to form a combined heavies stream, and catalytically cracking the combined heavies stream. Embodiment 8 is the method of any of embodiments 1 to 7, wherein the naphtha splitter includes heat exchangers, distillation columns, separators, pumps, absorbers, adsorbers, or combinations thereof. Embodiment 9 is the method of any of embodiments 1 to 8, wherein the naphtha splitter is operated under process conditions including an operating temperature of 30 to 50° C. Embodiment 10 is the method of any of embodiments 1 to 9, wherein the naphtha splitter is operated under process conditions including an operating pressure of 1 to 5 bar. Embodiment 11 is the method of any of embodiments 1 to 10, wherein the catalytically cracking is performed under process conditions including an operating temperature of 600 to 750° C. Embodiment 12 is the method of any of embodiments 1 to 11, wherein the catalytically cracking is performed under process conditions including an operating pressure of 1 to 4 bar. Embodiment 13 is the method of any of embodiments 1 to 12, wherein the catalytically cracking is performed in the presence of a molecular sieve based catalyst. Embodiment 14 is the method of any of embodiments 1 to 13, wherein the processing of the cracked stream includes compressors, separators, heat exchangers, pumps, dryers, coolers, reactors, distillation columns, extraction columns, or combinations thereof. Embodiment 15 is the method of any of embodiments 1 to 14, wherein the full range naphtha is obtained from distilling crude oil. Embodiment 16 is a method of processing full range naphtha. The method includes feeding the full range naphtha to a naphtha splitter, the full range naphtha having an IBP of 30 to 50° C. and a FBP of 210 to 220° C. The method further includes separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60 to 65° C. and a FBP of 210 to 220° C. and a light naphtha stream having an IBP of 30 to 35° C. and a FBP of 40 to 60° C. The method also includes catalytically cracking the heavy naphtha stream to produce a cracked stream, then processing the cracked stream to produce a stream containing primarily C₂ to C₄ olefins, benzene, toluene, xylene, collectively, a lights stream containing primarily C₂ to C₄ hydrocarbons, and a heavies stream containing primarily C₅ to C₁₂ hydrocarbons. In addition, the method includes combining the light naphtha stream with the lights stream to form a combined lights stream, and steam cracking the combined lights stream to produce olefins. Embodiment 17 is a method of producing olefins and/or BTX. The method includes the steps of splitting a feed stream comprising naphtha that has an IBP in a range of 30 to 50° C. and a FBP in a range of 210 to 220° C., preferably full range naphtha, to form a first stream containing heavy naphtha that has an IBP in a range of 60 to 65° C. and a FBP in a range of 210 to 220° C. and a second stream comprising light naphtha that has an IBP in a range of 30 to 35° C. and a FBP in a range of 40 to 60° C.; contacting the first stream with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in the first stream to form a first intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene; and subjecting the second stream to steam cracking conditions that comprises a temperature above 800° C. to convert hydrocarbons in the second stream and thereby form a second intermediate product stream containing one or more of: ethylene, propylene, butene, benzene, toluene, and xylene. Embodiment 18 is the method of embodiment 17, further including the step of flowing the first intermediate product stream and the second intermediate product stream to an oil quench tower; cooling the first intermediate product stream and the second intermediate product stream in an oil quench tower to produce an oil quench tower effluent stream; and separating the oil quench tower effluent stream into a product stream comprising primarily ethylene, a product stream comprising primarily propylene, and a product stream comprising primarily butadiene. Embodiment 19 is the method of any of embodiments 17 or 18 further including the step of recovering a recycle stream resulting from the separating step, wherein the recycle stream comprises primarily ethane, propane, n-butane, isobutane, 2-butene and recycling the recycle stream to the steam cracker. Embodiment 20 is the method of any of embodiments 17 to 19 further including the step of recovering a second recycle stream comprising primarily C₆+ hydrocarbons and recycling the second recycle stream to the catalytic cracking step. Embodiment 21 is the method of any of embodiments 17 to 20, wherein the oil quench tower effluent stream is at a temperature of 60° C. to 700. Embodiment 22 is the method of any of embodiments 17 to 21, wherein the oil quench tower is operated at a residence time of 1 to 120 minutes. Embodiment 23 is the method of any of embodiments 17 to 22, wherein the effluent of the oil quench tower is further quenched in a water quench tower prior to the separating step. Embodiment 24 is the method of embodiment 22, wherein the effluent of the oil quench tower is quenched in the water quench tower to a temperature of 60 to 800° C. Embodiment 25 is the method of any of embodiments 22 and 23, wherein the water quench tower is operated with a residence time of 1 to 120 minutes. Embodiment 26 is the method of any of embodiments 17 to 25, wherein the catalytic cracking conditions include a reaction temperature of 800 to 950° C. and a reaction pressure of 1 to 4 bar. Embodiment 27 is the method of any of embodiments 17 to 26, wherein the catalytic cracking conditions include a hydrocarbon to steam ratio of 0.1 to 5 and a gas hourly space velocity of 1 to 15000 hr-1. Embodiment 28 is the method of any of embodiments 16 to 26, wherein the catalyst in the contacting step comprises a molecular sieve based catalyst. Embodiment 29 is the method of any of embodiments 16 to 28, wherein the first intermediate product stream is cooled in a heat recovery unit before it is flowed to oil quench tower. Embodiment 30 is the method of any of embodiments 17 to 28, wherein the first intermediate product stream is cooled to a temperature of 60 to 700° C. in the heat recovery unit. Embodiment 31 is the method of any of embodiments 16 to 30, wherein the first intermediate product stream comprises 1 to 90 wt. % ethylene, 1 to 90 wt. % propylene, 1 to 90 wt. % C₄ hydrocarbons, 1 to 90 wt. % BTX, and/or 1 to 90 wt. % C₅+ hydrocarbons. Embodiment 32 is the method of any of embodiments 17 to 31, wherein the steam cracking conditions further include a residence time of 1 to 100 ms and steam to hydrocarbon ratio of 0.1 to 1. Embodiment 33 is the method of any of embodiments 16 to 32, wherein the separating step is carried out in a separation unit comprising one or more compressing units, one or more distillation units, one or more extraction units, one or more water washing units, one or more caustic tower, or combinations thereof. 

1. A method of processing full range naphtha, the method comprising: feeding the full range naphtha to a naphtha splitter, the full range naphtha having an initial boiling point (IBP) of 30 to 50° C. and a final boiling point of 210 to 220° C.; separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60 to 65° C. and a FBP of 210 to 220° C. and a light naphtha stream having an IBP of 30 to 35° C. and a FBP of 40 to 60° C.; catalytically cracking the heavy naphtha stream to produce a cracked stream; and processing the cracked stream in a processing unit to produce C₂ to C₄ olefins, benzene, toluene, and xylene.
 2. A method of producing olefins and/or BTX, the method comprising: splitting a feed stream comprising naphtha that has an initial boiling point in a range of 30 to 50° C. and a FBP in a range of 210 to 220° C. to form a first stream comprising heavy naphtha that has an initial boiling point in a range of 60 to 65° C. and a final boiling point in a range of 210 to 220° C. and a second stream comprising light naphtha that has an initial boiling point in a range of 30 to 35° C. and a final boiling point in a range of 40 to 60° C.; contacting the first stream with a catalyst under catalytic cracking conditions sufficient to cause cracking of hydrocarbons in the first stream to form a first intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene; and subjecting the second stream to steam cracking conditions that comprises a temperature above 800° C. to convert hydrocarbons in the second stream and thereby form a second intermediate product stream comprising one or more of: ethylene, propylene, butene, benzene, toluene, and xylene.
 3. A method of processing full range naphtha, the method comprising: feeding the full range naphtha to a naphtha splitter, the full range naphtha having an initial boiling point (IBP) of 30 to 50° C. and a final boiling point of 210 to 220° C.; separating the full range naphtha by the naphtha splitter, to produce a heavy naphtha stream having an IBP of 60 to 65° C. and a FBP of 210 to 220° C. and a light naphtha stream having an IBP of 30 to 35° C. and a FBP of 40 to 60° C.; catalytically cracking the heavy naphtha stream to produce a cracked stream; processing the cracked stream to produce a stream comprising primarily C₂ to C₄ olefins, benzene, toluene, xylene, collectively, a lights stream comprising primarily C₂ to C₄ hydrocarbons, and a heavies stream comprising primarily C₅ to C₁₂ hydrocarbons; combining the light naphtha stream with the lights stream to form a combined lights stream; and steam cracking the combined lights stream to produce olefins.
 4. The method of claim 1, further comprising steam cracking the light naphtha stream to produce olefins.
 5. The method of claim 1, wherein the processing further produces a lights stream comprising primarily C₂ to C₄ hydrocarbons, and a heavies stream comprising primarily C₅ to C₁₂ hydrocarbons.
 6. The method of claim 5, further comprising: combining the light naphtha stream with the lights stream to form a combined lights stream; and steam cracking the combined lights stream to produce a cracked lights stream comprising olefins.
 7. The method of claim 6, further comprising processing the cracked lights stream in the processing unit to produce additional C₂ to C₄ olefins.
 8. The method of claim 6, wherein the steam cracking is performed under process conditions including a cracking temperature of 800 to 950° C. and a residence time of 5 to 10000 ms.
 9. The method of claim 6, further comprising: combining the heavies stream and the heavy naphtha stream to form a combined heavies stream; and catalytically cracking the combined heavies stream.
 10. The method of claim 1, wherein the naphtha splitter comprises heat exchangers, distillation columns, separators, pumps, absorbers, adsorbers, or combinations thereof.
 11. The method of claim 1, wherein the naphtha splitter is operated under process conditions including an operating temperature of 30 to 50° C.
 12. The method of claim 1, wherein the naphtha splitter is operated under process conditions including an operating pressure of 1 to 5 bar.
 13. The method of claim 1, wherein the catalytically cracking is performed under process conditions including an operating temperature of 600 to 750° C.
 14. The method of claim 1, wherein the catalytically cracking is performed under process conditions including an operating pressure of 1 to 4 bar.
 15. The method of claim 1, wherein the catalytically cracking is performed in the presence of a molecular sieve based catalyst.
 16. The method of claim 1, wherein the processing of the cracked stream comprises compressors, separators, heat exchangers, pumps, dryers, coolers, reactors, distillation columns, extraction columns, or combinations thereof.
 17. The method of claim 1, wherein the full range naphtha is obtained from distilling crude oil.
 18. The method of claim 1, wherein the processing of the cracked stream comprises compressors.
 19. The method of claim 1, wherein the processing of the cracked stream comprises separators.
 20. The method of claim 1, wherein the processing of the cracked stream comprises distillation columns. 